Tag: energy transformations and energy transfers

Questions Related to energy transformations and energy transfers

An ice block is falling from a height. If $75\%$ of the block melts then $h = (g = 10\ ms^{-2})$.

  1. $10.2\ Km$

  2. $12.8\ Km$

  3. $25.2\ Km$

  4. $26.8\ Km$


Correct Option: A

A block of mass 500Kg has dimension $10 \times 5 \times 2m$. It is placed on a table with the largest surface in contract. The work that must be done to turn it an place it so that the smallest surface is in contact with the table  

  1. Zero

  2. 19600J

  3. 14700J

  4. 9800J


Correct Option: C

A lead ball moving with velocity v strikes a wall and stops. I 50% of its energy is converted into heat, then what will b the increase in temperature? (Specific heat of lead is s)

  1. $\dfrac { 2{ v }^{ 2 } }{ Js } $

  2. $\dfrac { { v }^{ 2 } }{ 4Js } $

  3. $\dfrac { { v }^{ 2 }s }{ J } $

  4. $\dfrac { { v }^{ 2 }s }{ 2J } $


Correct Option: B

In an energy recycling process, $x _ { g }$ of steam at $100 ^ { \circ } C$ becomes water at $100 ^ { \circ } \mathrm { C }$ which converts $\mathrm { Yg }$ of ice at $0 ^ { \circ } \mathrm { C }$ into water at $100 ^ { \circ } \mathrm { C }$ . The ratio XY will be

  1. $\dfrac { 1 } { 3 }$

  2. $\dfrac { 2 } { 3 }$

  3. $3$

  4. $2$


Correct Option: A

$4180 J$ of work raises the temperature of $1$ litre water through:-

  1. $1^oF$

  2. $10^oC$

  3. $1^oC$

  4. $273K$


Correct Option: C

The work done on the particle of mass m by a force $ \overrightarrow { F } =K\left[ \frac { X }{ \left( X^ 2+y^ 2 \right)^{1/2}  } \hat { i } +\frac { y }{ \left( X^ 2+y^ 2 \right)^{1/2}   } \hat { j }  \right]  $ (k being a constant of appropriate simensions), when the particle is taken from the point (a,0) to the point (0,a) along a circular path of radius a about the origin in the X-y plane 

  1. $ \frac {2k\pi}{a} $

  2. $ \frac {k\pi}{a} $

  3. $ \frac {k\pi}{2a} $

  4. 0


Correct Option: A

The maximum amount of work that can be done by extracting $1J$ of energy from a body at $127^oC$ with an environment at $27^oC$?

  1. $\dfrac{1}{8}J$

  2. $\dfrac{1}{4}J$

  3. $\dfrac{1}{2}J$

  4. $\dfrac{3}{4}J$


Correct Option: A

Which of the following energy conversions take place in a torch?

  1. electrical $\rightarrow$ chemical $\rightarrow$ light

  2. chemical $\rightarrow$ electrical $\rightarrow$ light

  3. electrical $\rightarrow$ light $\rightarrow$ chemical

  4. light $\rightarrow$ chemical $\rightarrow$ electrical


Correct Option: B
Explanation:

The chemicalenergy stored in batteries gets transformed into electrical energy through the wires. This then gets transformed into light energy that you see.

The glow worm produces light energy from

  1. Potential energy

  2. Nuclear fusion

  3. Electrical energy

  4. Chemical energy


Correct Option: D
Explanation:

Some organisms like the glow worm have chemicals in them, which produce light.

A fast moving motorbike mainly converts _______ energy to kinetic energy.

  1. chemical

  2. mechanical

  3. nuclear

  4. electrical


Correct Option: A
Explanation:

The chemical energy of the fuel is converted to kinetic energy using the engine of the bike.